Electric fuse



(No Model.)

W. E. HARRINGTON.

ELECTRIC FUSE.

No. 581,460. Patented Apr. 27, 1897.

WITNESSES UNITED STATES PATENT OFFIcE.

IVALTER E. HARRINGTON, OE PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE CUTTER ELECTRICAL AND Mr'tNUFACTURING COMPANY, OF NEIV JERSEY.

ELEGTREC FUSE.

SPECIFICATION forming part Of Letters Patent No. 581,460, dated April 27, 1897.

Application filed October 29, 1895. Serial No. 567,248. (No model.)

To aZZ whom it may concern: advisable in certain cases to firmly screw to Be it known that I, IVALTER E. IIARRING the terminal sections of the fuse metallic TON, acitizen of the United States, residingin buttons which should be situated at some the city and county of Philadelphia, State of distance from the primary section of the fuse, 5 5 Pennsylvania, have invented a certain new and which, when the terminal sections have and useful Improvementin Electric Fuses or burned back to them, will supply metallic Cut-Outs, of which the following is a true and vapor to maintain the are, but by dissipatexact description, reference being had to the ing the heat, owing to their relatively large accompanying drawings, which form a part masses, gradually check the supply of vapor 6o 10 thereof. until the arc is dissipated and the current My invention relates to what are known as ceases. The main function of the metallic electric fuses or cut-outs, being devices button is, however, the dissipation of the secured in electric circuits and fusing or heat, and therefore its place is filled to a burning in the transmission of electric curlarge degree by securing to or around the ter- 1 5 rents of greater amount than the main wires minal sections of the fuse masses of any subare intended to carry. As heretofore constance which will tend to dissipate the heat structed much trouble has occurred owing and by doing so check the burning of the to the burning or fusion of the terminals by metal and break the arc. The most efficient means of which the fuse is connected with materialsIhave found to be substances which 70 the main wires, this burning or fusion of the are liquid or semiliquid at a temperature beterminals being due to the fact that in the low that at which the terminal sections of the burning of the fuse the current is not at fuse will melt or burn, and which, by reason once interrupted, but is continued through an of this peculiarity, will, as the fuse is burned are made up largely of metallic vapor from down into them, close over its end and thus 75 the burningfuse and maintained through conafford a barrier to the passage of the metallic siderable distances by the progressive burnvapor upon which the are is maintained. ing of the fuse from the center toward the Preferably I employ substances which are. terminals, such burning continuing back to solid at ordinary temperatures and be fused and actually consuming a portion of the terat a comparatively low point, say 200 Fah- 80 a minals themselves in many cases. renheit, and among these substances I greatly The object of my invention is to provide a preferto employ those which infusing assume fuse the burning or blowing of which can a viscous condition, as material of this kind and will take place without injury to the tercan best be relied upon to close over the end minals of the main wire and generally to im of the burned fuse and is also less likely to 85 3 5 prove the construction of the fuse. escape. To prevent the escape of such ma- The leading feature of my invention conterial, I prefer to employ a casing or tube sists in making up a fuse with a primary cenwhich contains the liquid or liquefiable matral portion havinga cross-section determined terial and through which the terminal section by the amount of current it is intended to of the fuse passes, and preferably the ends 0 4o carry without blowing, and of terminal secof this tube or casing are sealed by non-contions or end pieces of greater cross-section ducting and infusiblo material. than the primary section and by which con- My invention relates to certain improvenection is made with the terminals of the ments in the block or casing in which the fuse main wires. By this construction I obviously situated and by which it is connected with insure that the burning of the fuse shall bethe line-wire. Theseimprovements, together gin in its central or primary part and also with certain details of the construction of the l provide metal which will burn more readily fuse which I have not above specifically re l l l l than the main terminals and by the combusferred to, will be best described in connection tion of which the arc instituted at the first with the drawings, in which 103 parting of the fuse is maintained, though with Figure 1 represents in perspective the fuse increasing resistance, I have also found it box and its lid, each part being shown separately, a fuse being illustrated in position within the box. Fig. 2 is central vertical. section through the fuse-box, the lid being shown in position. Fig. represents my fuse in its preferred form of construction, Fig. i being a section of a fuse embodying the general idea of my invention; 5, a section of a fuse such as is represented in Fig. 3; and Fig. 6, a view of a complete fuse, illustrating a modification.

A indicates the primary central section of the fuse proper. From each end of this primary section extend terminal sect-ions of greater cross-sectional area. Thus in Fig. la second wire is twisted together with terminals of the wire making up the primary section A to form the terminal section A of denble the area of A, and in Fig. 5 I show a construction in which the portion A of double the area of the portion A is supplemented by a portion A having three times the sectional area of A and making up the final terminals of the fuse-wire.

At B, I indicate the enveloping mass of material which I prefer to use in connection with the terminal sections of the fuse, both to dissipate the heat and preferably also to furnish a liquid seal to close over the end of the fuse-section when it is burned down into the surrounding mass. In case of the use of sealing-wax or like material it is evident that it can be melted around the wire with a surrounding jacket or casing, but manifestly the use of a containing-jacket, such as indicated at C, is always preferable, and I have found that sections of glass tubes will answer in a very satisfactory way for such casings, the terminal sections of the fuse being passed through the tubes and the filling material 13 run into the tubes and allowed to solidify therein. Preferably I seal the ends of the tubes by plugs D of infusible non-conducting material, such as plaster-ofparis. These plugs will prevent the escape of the liquefied material in the tubes, at least until after it has performed its function in breaking the arc, and obviously it would be practicable, when the ends of the tubes are hermetically sealed, to use a filling material 13, which is liquid even at normal temperature. 13y preference I form my fuse with the intermediate sections A, between the primary section A and the terminal sections A and I cause the mass of material B, relied upon for interrupting the arc, to extend over the joint be tween A and A but not over the joints between A and the primary section A.

At A, I have indicated a metallic button secured on the terminal sections of the fusewire and surrounded by the liquetiable ma terial B. This construction will, I believe, be found advantageous in dealing with cer tain currents of high voltage, the buttons A not only serving, as does the material B, to dissipate the heat, but furnishing a reservoir of metal which will prevent the burning of the fuse from extending back toward the mainline terminals and supply metallic vapor to keep up the are through an appreciable time which will probably be sufficient to insure the breaking of the arc and of the current passing through it.

E indicates the fuse-block, having chambers E" E" for containing the terminals of the main wire and chambers E E for containing the terminal sections of the fuse. The chambers It are separated from each other by the bridge-wall E and from the chambers It? by the bridge-wall E, while the chambers E are separated from each other by the bridge-wall E.

E I and indicate groov .s in the tube of the bridge-walls mentioned, into which fit ridges F F and F 01? the block-lid F, which also has an edge rib F, which fits down into a depressed seat Idon the edge of the block it.

E and F representregistering openings in the block and its lid by which the main-line wires if K enter the chambers It. At the end of the chambers It is formed the flared chamber E", which, together with the flared portion F of the lid, makes up the blowchamber of the fuse-block.

F. is a cavity formed in the back of the block E, E being a continuation of smaller diameter. The corresponding portion of the lid F is provided with a raised portion F, slotted as indicated at F. Through the perforation E E passes bolt G, having a thumbhead G at one end and a round head G at the other. A spring I I is situated in the cavity E and retained in place by the head G IVhen the lid is to be placed on the f use-block, the thumb-head G is turned to the position indicated in dotted lines in Fig. (3, when it will readily pass through the slot F It is then turned outward until it lies above the platform F and turned, as indicated in full lines, so as to-rest on the platform on each side of the slot. The two portions E and F of the fuse-block are thus held together by the resilient action of the spring II, which will yield to a sufficient extent in case of any explosive action occurring in the burning of the fuse to prevent material harm.

It E indicate screw-holes by which the fuse-block can be secured to a wall through screws I, as indicated in Fig. 6.

.I J indicate terminals of the main-line wires to which the terminal sections of the fuse proper are secured also, these terminal sections passing through small perforations in the wall E, as indicated in Fig. 1.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. An electric fuse having a central primary section, terminal sections of greater cross-section and masses of non-conducting material arranged to surround portions of each of said terminal sections without inclosing the central primary section.

2. An electric fuse having a central primary section, terminal sections of greater cross-section, and masses of fusible non-com ducting material arranged to surround portions of each of said terminal sections without inclosing the central primary section.

3. An electric fuse having a central primary section, and terminal sections of greater cross-section in combination with metallic buttons secured to said terminal sections, and non-conducting material inclosing said buttons and the portions of the terminal sections adjacent thereto.

4. An electric fuse having a primary central section and terminal sections of greater cross-section in combination with tubes B surrounding the terminal sections but not inclosing the central section, and a tube-fillin g of non-conducting material liquid at temperatures below that at which the terminal sections fuse.

5. An electric fuse having a primary central section and terminal sections of greater cross-section in combination with tubes B surrounding the terminal sections but not inclosing the central section and a tube-filling of nonconducting material solid at ordinary temperatures but fusible at temperatures below that at which the terminal scctions fuse.

(3. An electric fuse having a primary central section and terminal sections of greater cross-section in combination with tubes B surrounding the terminal sections but not inclosing the central section and a tube-fill in g of sealing-wax or equivalent material.

' 7. An electric fuse having a primary cen tral section and terminal sections of greater cross-section in combination with tubes B surrounding the terminal sections, but not inclosing the central section, a tube-filling of non-conducting material liquid at temperatures below that at which the terminal 

